Stefan's 1920's victim list is a hidden list in Stefan's old apartment in Chicago. It's a list of every man, woman or child that he killed during his 'ripper days'. Stefan used the list to record and relive each and every kill. The list is first seen in the episode, The End of the Affair, during Season Three.
It was revealed in the Season Three Blu-ray Exclusive, that the cast put names of the people they knew on the list (ex: Nina Dobrev's mom, crew member's name).